Lathe Chuck thread size

[Bootlegger BlackyParticipant @bootleggerblacky]

Hi everyone,I have a couple of old lathe chucks with a thread size of 7/8”.11 tpi.

any idea what machine these could be off?

 

[jim1956Participant @jim1956]

lathes.co.uk/bsw  says a 7/8″ nose, no tpi mentioned just 7/8Whit.

How confident are you in the 11tpi, the normal 7/8 Whitworth would be 9tpi.

Regards Jim

Edited to add.

Just looked up 7/8″ BSF  (same 55 degree thread form as Whitworth) but 11tpi.

[DC31kParticipant @dc31k]

There is a post here where someone says they have a Myford ML4 with a non-standard spindle nose that has that thread.

Myford ML4 headstock thread size

And one here which says Faircut Senior:

https://sites.google.com/site/mistergriffithsworkshop/past-projects/lathe-chuck-backplate

 

[peak4Participant @peak4]

Search Tony’s site for 7/8″ BSF; here’s one result

https://www.lathes.co.uk/boxford/page5.html

Bill

[Howard LewisParticipant @howardlewis46836]

The ML3 and 4 changed from 7/8 x 9 (7/8 BSW.)  to 7/8 x 12 tpi (Whit form) over time.

Might be worth rechecking the pitch?

Howard

[Author]

Posts